Notching the shell edge for permanent marking
Marking of turtles for individual recognition may be required under some circumstances, for example when detailed information on demography, survivorship, or movement patterns are needed. Note that permits are required for capturing, handling, and marking of turtles. A common method of marking turtles involves filing notches to the edge of peripheral scutes of the carapace. There are several ways to number the scutes. The scheme outlined in the Resource Inventory Standard Committee's manual for Pond-breeding Amphibians and Painted Turtle has been adopted by the B.C. Western Painted Turtle Working Group.
Notches are filed in the middle edge of the peripheral scutes using a triangular file (e.g., 15 cm long; 0.7 cm wide). Most turtles have 12 scutes (partitions on the edge of their shell) on either side of their carapace , excluding one small central scute (0) at the top of the carapace behind the head. However, for marking purposes scutes 4,5 and 6 are skipped to avoid the thickest part of the shell with the most vascularisation and also to avoid turtles rubbing the notches with their limbs and causing injury. The scutes that are used are numbered right or left 1 through to 9. The first scutes on one side can be designated as a location (water body) identifier, and one of these scutes is notched in all turtles from a specific location. The notches should be disinfected after filing.
Figure 1. Top view of carapace with numbering scheme. In example, marked scute on left side indicates waterbody number: 3 and marked scute on right side indicates individual number: 2.
Using file to notch turtle carapace
Marking of hatchling turtles is sometimes desirable, for example to evaluate predation rates or effectiveness of head-starting programs. Visible Implant Elastomers have been used with success to mark hatchling Snapping Turtles. A small, fluorescent tag is injected sub-cutaneously on the underside of the hindleg. The marks are permanent and appear to cause no adverse effects. This marking system has been used with success for amphibians (REF).
- ↑ Resource Inventory Standard Committee. 1998a. Inventory methods for pond-breeding amphibians and painted turtle. Standards for components of British Columbia’s Biodiverslty No. 37. Resource Inventory Branch, Ministry of Environment, Lands and Parks (available at http://www.ilmb.gov.bc.ca/risc/pubs/tebiodiv/pond/assets/pond.pdf). pp 94
- ↑ Davy, C.M., S.M. Coombes, A.K. whitear, and A.S. MacKenzie. 2010. Visible implant elastomer: a simple non-harmful method for marking hatchling turtles. Herp. Review 41(4): 442-445.